Nickel Zinc batteries have been around for years and earlier this year I embarked on a 8 month trial using the Powergenix AA NiZn batteries for my strobes, both topside and underwater. NiZn has no fewer toxic metals (as in no Mercury, Cadmium etc) and the elements Nickel and Zinc are more easily and fully recyclable. The advantage of NiZn is the high nominal voltage of 1.65V vs 1.2-3V of NiMH and NiCD. The power draw of the battery is slight better than Ni-Cd which is better than NiMH. There is plenty of proof on youtube about the fast strobe recycling NiZn allows. On average, I've non-scientifically estimated around a 30-40% decrease in recharge time to full power. So if your strobe takes 2 seconds to fully charge up to full power, the NiZn battery can cut it down to 1.2 seconds. The charge life in strobe terms is about the same as the Maha Immedion, where I shoot over 150 full power shots, which is good enough for me. For fast strobe recycling time, NiZn is definitely the battery to have. A nice feature of the high voltage draw is that the performance will keep going about the same way until the battery is drained, whereas there is a distinct curve to NiMH, which means slower recharge times as it drains.The marketing is a little fuzzy. They use mWh, when most batteries use mAh. To get equivalency, a Maha Imedion 2100mAh battery has 2520mWh, which is virtually identical to the Powergenix 2500mWh at nominal voltage rating. Or it has about 1500mAh @ 1.65V.There are a few caveats. OFF GAS: NiZn is known to off gas a bit (like NiMH does). When I used it the Inon Z240, it fired very well but if I leave freshly charged batteries in the Inon overnight, the off-gas builds up pressure, which, at worst, can cause the strobe to leak or at the least, pop the cap off while you open it. My normal workflow is always to put in fresh batteries in the morning and not leave batteries in the strobes. For those who like to set up the strobes the night before, you will need to revise your workflow to use NiZn batteries.Average Charger:Another thing is the charger is only ok fast, taking about 2.5-3 hrs to fully charge 4 AA batteries. One big bummer is you can't use your old NiMH chargers, but you can use the Maha C9000 to test the charge. It won't tell you how healthy the battery is though. So basically, you have to buy a specific charger for NiZn batteries, which also can't charge NiMH batteries. It is cooler after charging compared to NiMH batteries.Life Cycle is a bit murky: A dirty little unmentioned fact of this NiZn is the cycle life compared to NiMH/NiCd batteries. I did a bit of Googling but found no evidence of Powergenix stating what the cycle life is for the batteries. With NiCd/NiMH rated up to 1000 deep discharges, Powergenix's claim to meet this specification. However, some people think it is around 200 deep discharge cycles, based on documents found on Powergenix's website. I could not find such a document anymore but found it linked elsewhere. I've had them on 60 cycles or so and they still work well.High Voltage burn out: The high voltage of the battery (sometimes over 1.8V after charging) can fry unregulated devices like torchlights etc.I tried it on my LED light and it worked fine. Same thing goes for strobes as the bulb may burn out due to thermal overload from rapid firing at full power!Self-Discharge is average: This battery is about the same as normal NiMH batteries (but not the slow-discharge NiMH like Eneloop and Imedion) on discharge. It does mean they have to be recharged when not used for while.

So why am I raving about these batteries? They've more environmentally friendly and the power draw is fast, making a normal strobe feel like it's on steroids when it comes to recycling. This is very useful for full power shots from my Inon Z240 while shooting wideangle animal behavior, where a few rapid fire shots may be required. It is a pity it is only available in AA cells now. Do I recommend using it as a replacement to AA NiMH? For strobes, yes. For everything else, I'll have to see in about 8 mths time when it gets older and how long it lasts. It costs about the same as the NiMH batteries. The need to be recharged after storage is a negative but it does last longer than the Eneloops in my tests. However Imedion recently released their 2400mAh slow discharge AA battery, which may even the endurance performance a bit. That said, NiZn is the choice for fast cycling strobes, bar none.

That's interesting Ryan. I've found the batteries to be cooler than the Eneloops/Imedions which are approved. The off gassing issue is of concern but since my Inons are way out of warranty and I've found the pressure build up is only a real issue straight out of the charger. So long as I don't keep them sealed up in the strobe, it seems fine. The recharge time is so much faster I feel the risk is worth it, plus I don't use the guide light anyhow.
However, thanks for pointing out that IF anyone uses these batteries while in warranty, you may have issues with Inon.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

You said "The charge life in strobe terms is about the same as the Maha Immedion" Do you mean the no. of full power pops on the strobe? I just took delivery of a set of Imedion 2400's for my aging (but reliable) S&S YS120s and will be using them shortly.

Stu
I only have the 2100 Imedions and the strobe would recharge longer and slower as the battery wore out near the end. I shot about 260+ shots and it was noticeably wheezing as it discharged. The NiZn had about the same number of shots (probably a few more than the Imedion) but the difference it kept shooting with fast recycling then wheezed for 10+ frames before it went dead. I much prefer that sort of power curve.
Of the NiMH, the Eneloops recycled slightly faster than the Imedion, but had fewer shots. This is using my 580EX and not the Inon, but the results should stand for the Inon Z240 too.
Your new 2400mAh should take about 10% more pics than the older 2100 Imedion but probably won't cycle faster.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

OK, Thanks Drew. I was really tempted to try those out, but to buy a minimum of 32 batteries, and likely 4 chargers...on top of the NiMH cells that I use for lights and topside flash...bit too much with a 50lb limit!

I started with 16 aa's and 2 chargers... just for strobes, both topside and uw. I'm phasing out the NiMH to my household, since the self discharge rate of the Eneloop type batteries are still superior to NiZn and are more suited for remote controls, flashlights etc. I'm not sure if NiZn is ready for primetime yet. The longevity is a question mark, and while the chemistry was patented by Edison 100 years ago, recent attempts at the market with NiZn car batteries had issues with chargers and fell flat. It's in its infancy but the lower environmental impact and recycling speed are definitely the drawcards for me.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

I guess my experience in testing them is a bit different than Drew's. First I agree that they recycle a lot faster in my Inon strobes than NiMH batteries but at least twice after a dive they generated so much pressure on an S2000 that it was ridiculously hard to remove the cap and when the cap came off, the battery contacts shot off with quite a pop. More to the point, in computerized battery testing using a duty cycle of 15 second discharge (3A) and 30 seconds of no discharge, the NiZn batteries could deliver about 60% of rated capacity (mAh, not mWh) while the newer 2400 mAh batteries under the same cycle could deliver more like 85% of their rated capacity. Given that the rated capacity of the NiZn batteries is only about 75% of the NiMH batteries the NiZn could in reality only deliver about 42% or so as much current as the NiMh in a duty cycle test. I was surprised by the results but they seem quite reproducible over 8 NiZn batteries and 15 or so low discharge NiMH versions.

That's great to have other people's feedback, Bill. It's very important to get the full picture.
I had the pressure build up issue a few times but since I don't overtighten (in fact I under tighten) the cap, it's less effort. I don't have the S2000 but once the cap is off the Z240, the pressure is released and the contacts (which is fastened by screw to the strobe body) don't bounce off as you experienced with the S2000.
What I didn't get was the excessive pressure build up during a dive. And I usually shoot in rapid mode to stress the batteries (and probably shorten the bulb life). I still get about 150 full power shots and over 260 of mixed power shooting. Perhaps it's the size difference between the Z240 and S2000. I think the Inon battery compartments are supposedly sealed off in the Z240.
Your test cycle results indicate that the NiZn batteries don't last as long as the NiMH, and my usage showed while it had capacity, the power curve was better than NiMH, whose voltage dipped as it discharged, to the point where it was slow in recharging the strobe. So the power curve is a lot more steady for NiZn, but doesn't last as long as NiMH.
I'll still use them for rapid fire duty but as you have warned, the pressure build varies for different strobes so test your strobes topside before taking them into water.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

The first batch of 8 just hit a wall and are beginning to show signs of lost capacity. I don't have my tester to see what the charge is but it died after about 100 shots at full power yesterday and that's off a 580EX. These batteries have been charged about 100 times. I have another 16 which I will pay more attention to. They are still the fast recycling champs but if they are throwaway after 150 cycles then I'll have to reconsider them as a replacement for NIMH.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

It's NOT true that nickel is non-toxic. It's in fact rather highly toxic as heavy metals go, and it doesn't take much in the body to cause severe problems. Many if not most nickel factory workers were poisoned in the old and not-so-old days.

In Germany, there was a recent scandal when it was discovered by testing that the cheaper kind of electric kettle ("Wasserkocher"), as found in every German kitchen, with the exposed nickel-plated steel heating element in contact with the water, was putting worrisome amounts of nickel into everyone's hot water. I threw ours out. (Better and newer ones have the heating element beneath a stainless-steel bottom plate.)

Zinc in small amounts is needed for health, and not nearly as toxic.

So, like all other batteries, these should never be taken apart and must be properly recycled, at a facility that can handle this new chemistry.

It's NOT true that nickel is non-toxic. It's in fact rather highly toxic as heavy metals go, and it doesn't take much in the body to cause severe problems. Many if not most nickel factory workers were poisoned in the old and not-so-old days. So, like all other batteries, these should never be taken apart and must be properly recycled, at a facility that can handle this new chemistry.

Interesting about the mixed results posted in the comments. I still use mine in the strobes when I want rapid fire ability. I did find another company making NiZn batteries for cars while searching to replace my car batteries and their product specs NiZn to be less than 1/2 of NiMH in full recycles. Their specs were about 300-500 for NiZn and 600-1200 for NiMH.

As Bill's tests show, under controlled strobe conditions, NiZn is going to lose out to NiMH on charge. But for rapid fire purposes, the NiZn will win, and it's a little easier to recycle the materials.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

Well I forgot to update this thread but I'm on my 3rd set of NiZns after the first 2 batches died of use. 1st batch, 60% died after 60-80 recycles and I managed to squeeze 100 recycles out of 4. They've also dropped like hell in price ($15.99 for 4 AA with fast charger or 1 8 pack)
2nd batch, most died before 60 cycles (of relative continuous use, within 3 mths). I sent them back for warranty replacement and got new batteries. The failure rate is pretty bad compared to NiMH batteries.

BUT they still cut recycling time by at least 40% and if you want the fastest recycling time (and risk frying your flash unit, which overheats rapidly with repeated firing) they are still the one choice.

I've switched from using just the EX580 II to the EX320, because there's a LED for impromptu video. The NiZN recycle fast but with LED use , the battery life is like 70% of NiMH (if I'm generous). There's also talk of the overvoltage issue with LED so I went back to NiMH with the EX320.

I'll still keep an 8 pack around because of the recycling time but I've stopped using them for the Inons, because I have strobes that fire 10fps without sweating and the Inons weren't designed for that.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

That's a mouthful of a name! What is the difference between these and the XX batteries? Are these precharged? The Immedion 2400mah are a little cheaper and compare very well with the Eneloop XX 2500mah, which is currently the king of the hill for low discharge NiMH.

Drew
Moderator
"Journalism is what someone else does not want printed, everything else is public relations."

"I was born not knowing, and have only had a little time to change that here and there.

That's a mouthful of a name! What is the difference between these and the XX batteries? Are these precharged? The Immedion 2400mah are a little cheaper and compare very well with the Eneloop XX 2500mah, which is currently the king of the hill for low discharge NiMH.

I have been using and recommending the Eneloop XX 2.5 mah for a month now....good enough for three dives in a Z240 (unless its full dump each time). I am thinking of using these for my Seaflash Digital 150 battery mod. highspeed flashes really drains the original batteries.